diff --git a/synapse/rest/media/v1/preview_url_resource.py b/synapse/rest/media/v1/preview_url_resource.py
index 0f051d4041..f108da05db 100644
--- a/synapse/rest/media/v1/preview_url_resource.py
+++ b/synapse/rest/media/v1/preview_url_resource.py
@@ -22,7 +22,7 @@ import re
import shutil
import sys
import traceback
-from typing import TYPE_CHECKING, Any, Dict, Generator, Iterable, Optional, Union
+from typing import TYPE_CHECKING, Dict, Generator, Iterable, Optional, Union
from urllib import parse as urlparse
import attr
@@ -43,6 +43,8 @@ from synapse.logging.context import make_deferred_yieldable, run_in_background
from synapse.metrics.background_process_metrics import run_as_background_process
from synapse.rest.media.v1._base import get_filename_from_headers
from synapse.rest.media.v1.media_storage import MediaStorage
+from synapse.rest.media.v1.oembed import OEmbedError, OEmbedProvider
+from synapse.types import JsonDict
from synapse.util import json_encoder
from synapse.util.async_helpers import ObservableDeferred
from synapse.util.caches.expiringcache import ExpiringCache
@@ -71,65 +73,44 @@ OG_TAG_VALUE_MAXLEN = 1000
ONE_HOUR = 60 * 60 * 1000
-# A map of globs to API endpoints.
-_oembed_globs = {
- # Twitter.
- "https://publish.twitter.com/oembed": [
- "https://twitter.com/*/status/*",
- "https://*.twitter.com/*/status/*",
- "https://twitter.com/*/moments/*",
- "https://*.twitter.com/*/moments/*",
- # Include the HTTP versions too.
- "http://twitter.com/*/status/*",
- "http://*.twitter.com/*/status/*",
- "http://twitter.com/*/moments/*",
- "http://*.twitter.com/*/moments/*",
- ],
-}
-# Convert the globs to regular expressions.
-_oembed_patterns = {}
-for endpoint, globs in _oembed_globs.items():
- for glob in globs:
- # Convert the glob into a sane regular expression to match against. The
- # rules followed will be slightly different for the domain portion vs.
- # the rest.
- #
- # 1. The scheme must be one of HTTP / HTTPS (and have no globs).
- # 2. The domain can have globs, but we limit it to characters that can
- # reasonably be a domain part.
- # TODO: This does not attempt to handle Unicode domain names.
- # 3. Other parts allow a glob to be any one, or more, characters.
- results = urlparse.urlparse(glob)
-
- # Ensure the scheme does not have wildcards (and is a sane scheme).
- if results.scheme not in {"http", "https"}:
- raise ValueError("Insecure oEmbed glob scheme: %s" % (results.scheme,))
-
- pattern = urlparse.urlunparse(
- [
- results.scheme,
- re.escape(results.netloc).replace("\\*", "[a-zA-Z0-9_-]+"),
- ]
- + [re.escape(part).replace("\\*", ".+") for part in results[2:]]
- )
- _oembed_patterns[re.compile(pattern)] = endpoint
+@attr.s(slots=True, frozen=True, auto_attribs=True)
+class MediaInfo:
+ """
+ Information parsed from downloading media being previewed.
+ """
-@attr.s(slots=True)
-class OEmbedResult:
- # Either HTML content or URL must be provided.
- html = attr.ib(type=Optional[str])
- url = attr.ib(type=Optional[str])
- title = attr.ib(type=Optional[str])
- # Number of seconds to cache the content.
- cache_age = attr.ib(type=int)
+ # The Content-Type header of the response.
+ media_type: str
+ # The length (in bytes) of the downloaded media.
+ media_length: int
+ # The media filename, according to the server. This is parsed from the
+ # returned headers, if possible.
+ download_name: Optional[str]
+ # The time of the preview.
+ created_ts_ms: int
+ # Information from the media storage provider about where the file is stored
+ # on disk.
+ filesystem_id: str
+ filename: str
+ # The URI being previewed.
+ uri: str
+ # The HTTP response code.
+ response_code: int
+ # The timestamp (in milliseconds) of when this preview expires.
+ expires: int
+ # The ETag header of the response.
+ etag: Optional[str]
-class OEmbedError(Exception):
- """An error occurred processing the oEmbed object."""
+class PreviewUrlResource(DirectServeJsonResource):
+ """
+ Generating URL previews is a complicated task which many potential pitfalls.
+ See docs/development/url_previews.md for discussion of the design and
+ algorithm followed in this module.
+ """
-class PreviewUrlResource(DirectServeJsonResource):
isLeaf = True
def __init__(
@@ -157,6 +138,8 @@ class PreviewUrlResource(DirectServeJsonResource):
self.primary_base_path = media_repo.primary_base_path
self.media_storage = media_storage
+ self._oembed = OEmbedProvider(hs, self.client)
+
# We run the background jobs if we're the instance specified (or no
# instance is specified, where we assume there is only one instance
# serving media).
@@ -275,18 +258,17 @@ class PreviewUrlResource(DirectServeJsonResource):
logger.debug("got media_info of '%s'", media_info)
- if _is_media(media_info["media_type"]):
- file_id = media_info["filesystem_id"]
+ if _is_media(media_info.media_type):
+ file_id = media_info.filesystem_id
dims = await self.media_repo._generate_thumbnails(
- None, file_id, file_id, media_info["media_type"], url_cache=True
+ None, file_id, file_id, media_info.media_type, url_cache=True
)
og = {
- "og:description": media_info["download_name"],
- "og:image": "mxc://%s/%s"
- % (self.server_name, media_info["filesystem_id"]),
- "og:image:type": media_info["media_type"],
- "matrix:image:size": media_info["media_length"],
+ "og:description": media_info.download_name,
+ "og:image": f"mxc://{self.server_name}/{media_info.filesystem_id}",
+ "og:image:type": media_info.media_type,
+ "matrix:image:size": media_info.media_length,
}
if dims:
@@ -296,14 +278,14 @@ class PreviewUrlResource(DirectServeJsonResource):
logger.warning("Couldn't get dims for %s" % url)
# define our OG response for this media
- elif _is_html(media_info["media_type"]):
+ elif _is_html(media_info.media_type):
# TODO: somehow stop a big HTML tree from exploding synapse's RAM
- with open(media_info["filename"], "rb") as file:
+ with open(media_info.filename, "rb") as file:
body = file.read()
- encoding = get_html_media_encoding(body, media_info["media_type"])
- og = decode_and_calc_og(body, media_info["uri"], encoding)
+ encoding = get_html_media_encoding(body, media_info.media_type)
+ og = decode_and_calc_og(body, media_info.uri, encoding)
# pre-cache the image for posterity
# FIXME: it might be cleaner to use the same flow as the main /preview_url
@@ -311,14 +293,14 @@ class PreviewUrlResource(DirectServeJsonResource):
# just rely on the caching on the master request to speed things up.
if "og:image" in og and og["og:image"]:
image_info = await self._download_url(
- _rebase_url(og["og:image"], media_info["uri"]), user
+ _rebase_url(og["og:image"], media_info.uri), user
)
- if _is_media(image_info["media_type"]):
+ if _is_media(image_info.media_type):
# TODO: make sure we don't choke on white-on-transparent images
- file_id = image_info["filesystem_id"]
+ file_id = image_info.filesystem_id
dims = await self.media_repo._generate_thumbnails(
- None, file_id, file_id, image_info["media_type"], url_cache=True
+ None, file_id, file_id, image_info.media_type, url_cache=True
)
if dims:
og["og:image:width"] = dims["width"]
@@ -326,12 +308,11 @@ class PreviewUrlResource(DirectServeJsonResource):
else:
logger.warning("Couldn't get dims for %s", og["og:image"])
- og["og:image"] = "mxc://%s/%s" % (
- self.server_name,
- image_info["filesystem_id"],
- )
- og["og:image:type"] = image_info["media_type"]
- og["matrix:image:size"] = image_info["media_length"]
+ og[
+ "og:image"
+ ] = f"mxc://{self.server_name}/{image_info.filesystem_id}"
+ og["og:image:type"] = image_info.media_type
+ og["matrix:image:size"] = image_info.media_length
else:
del og["og:image"]
else:
@@ -357,98 +338,17 @@ class PreviewUrlResource(DirectServeJsonResource):
# store OG in history-aware DB cache
await self.store.store_url_cache(
url,
- media_info["response_code"],
- media_info["etag"],
- media_info["expires"] + media_info["created_ts"],
+ media_info.response_code,
+ media_info.etag,
+ media_info.expires + media_info.created_ts_ms,
jsonog,
- media_info["filesystem_id"],
- media_info["created_ts"],
+ media_info.filesystem_id,
+ media_info.created_ts_ms,
)
return jsonog.encode("utf8")
- def _get_oembed_url(self, url: str) -> Optional[str]:
- """
- Check whether the URL should be downloaded as oEmbed content instead.
-
- Args:
- url: The URL to check.
-
- Returns:
- A URL to use instead or None if the original URL should be used.
- """
- for url_pattern, endpoint in _oembed_patterns.items():
- if url_pattern.fullmatch(url):
- return endpoint
-
- # No match.
- return None
-
- async def _get_oembed_content(self, endpoint: str, url: str) -> OEmbedResult:
- """
- Request content from an oEmbed endpoint.
-
- Args:
- endpoint: The oEmbed API endpoint.
- url: The URL to pass to the API.
-
- Returns:
- An object representing the metadata returned.
-
- Raises:
- OEmbedError if fetching or parsing of the oEmbed information fails.
- """
- try:
- logger.debug("Trying to get oEmbed content for url '%s'", url)
- result = await self.client.get_json(
- endpoint,
- # TODO Specify max height / width.
- # Note that only the JSON format is supported.
- args={"url": url},
- )
-
- # Ensure there's a version of 1.0.
- if result.get("version") != "1.0":
- raise OEmbedError("Invalid version: %s" % (result.get("version"),))
-
- oembed_type = result.get("type")
-
- # Ensure the cache age is None or an int.
- cache_age = result.get("cache_age")
- if cache_age:
- cache_age = int(cache_age)
-
- oembed_result = OEmbedResult(None, None, result.get("title"), cache_age)
-
- # HTML content.
- if oembed_type == "rich":
- oembed_result.html = result.get("html")
- return oembed_result
-
- if oembed_type == "photo":
- oembed_result.url = result.get("url")
- return oembed_result
-
- # TODO Handle link and video types.
-
- if "thumbnail_url" in result:
- oembed_result.url = result.get("thumbnail_url")
- return oembed_result
-
- raise OEmbedError("Incompatible oEmbed information.")
-
- except OEmbedError as e:
- # Trap OEmbedErrors first so we can directly re-raise them.
- logger.warning("Error parsing oEmbed metadata from %s: %r", url, e)
- raise
-
- except Exception as e:
- # Trap any exception and let the code follow as usual.
- # FIXME: pass through 404s and other error messages nicely
- logger.warning("Error downloading oEmbed metadata from %s: %r", url, e)
- raise OEmbedError() from e
-
- async def _download_url(self, url: str, user: str) -> Dict[str, Any]:
+ async def _download_url(self, url: str, user: str) -> MediaInfo:
# TODO: we should probably honour robots.txt... except in practice
# we're most likely being explicitly triggered by a human rather than a
# bot, so are we really a robot?
@@ -459,11 +359,11 @@ class PreviewUrlResource(DirectServeJsonResource):
# If this URL can be accessed via oEmbed, use that instead.
url_to_download: Optional[str] = url
- oembed_url = self._get_oembed_url(url)
+ oembed_url = self._oembed.get_oembed_url(url)
if oembed_url:
# The result might be a new URL to download, or it might be HTML content.
try:
- oembed_result = await self._get_oembed_content(oembed_url, url)
+ oembed_result = await self._oembed.get_oembed_content(oembed_url, url)
if oembed_result.url:
url_to_download = oembed_result.url
elif oembed_result.html:
@@ -560,18 +460,18 @@ class PreviewUrlResource(DirectServeJsonResource):
# therefore not expire it.
raise
- return {
- "media_type": media_type,
- "media_length": length,
- "download_name": download_name,
- "created_ts": time_now_ms,
- "filesystem_id": file_id,
- "filename": fname,
- "uri": uri,
- "response_code": code,
- "expires": expires,
- "etag": etag,
- }
+ return MediaInfo(
+ media_type=media_type,
+ media_length=length,
+ download_name=download_name,
+ created_ts_ms=time_now_ms,
+ filesystem_id=file_id,
+ filename=fname,
+ uri=uri,
+ response_code=code,
+ expires=expires,
+ etag=etag,
+ )
def _start_expire_url_cache_data(self):
return run_as_background_process(
@@ -717,7 +617,7 @@ def get_html_media_encoding(body: bytes, content_type: str) -> str:
def decode_and_calc_og(
body: bytes, media_uri: str, request_encoding: Optional[str] = None
-) -> Dict[str, Optional[str]]:
+) -> JsonDict:
"""
Calculate metadata for an HTML document.
|
